This study analyzes the influential factors including the aerosol type, relative humidity (RH), atmospheric boundary layer height (BLH), wind speed and direction, and aerosol vertical structure to the AOD-PM2.5
relationship. It shows that the ratio of PM2.5
to AOD, η
, varies a lot with aerosol type. η
is smaller for scattering-dominant (coarse mode) than for absorbing-dominant (fine mode) aerosol. The higher the RH (BLH), the larger (smaller) the η
also decreases with the surface wind speed.